We changed the two moderate-sized wheels to two Lego motorcycle wheels.

We changed the two Lego motorcycle wheels to two
2cm-diameter tyreless Lego wheels.

We changed the two 2cm-diameter tyreless Lego wheels to 1 Lego motorcycle wheel with tyre.

State rationale(s) for the above proposed modification

The wheels were too bulky in terms of their width and is interrupted by the leverage such that when it fully extends it comes in contact with the front wheels and stops the mousetrap car from moving further.

Though the wheels were thinner now, it was still in the way of the leverage. When the leverage fully extends, it shuts fully but grazes against the wheels.

Though everything seems complete, we are not impressed with ourselves going only 5.5 metres. We figured that the front wheels could not keep the car going despite the inertia built up. So we changed the wheels to one original motorcycle wheel.